Probably not, if she has not threatened you. Nevertheless, it may be helpful to speak to a MA attorney and/or your boyfriend's divorce attorney about your options to have her cease her behavior.
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If the woman is making false statements about you to others that are harmful to your reputation, embarrassing and/or injurious to you, then you may have a decent civil suit against her for libel/slander. If she is making false and damaging statements about you in her pleadings and also making false and damaging statements about you to other parents, etc., then she is committing a tort against you. Think about this: can you prove it? if you get a judgment does she have the ability to pay or is she broke? And, even if the answers are not strong to the previous two questions, filing a suit against her, one that has merit, might get her to stop. You might want to talk with an attorney about this.